How to move bones with IK?
You need to create a controller bone that will control your IK:


Create a bone from the last one and deparent it with alt P.
Deactivate the Deform option of this bone so that this bone won't deform the mesh of your object when you'll parent it to the armature.
Choose this new bone as the Target of your IK bone.
Move the controller, the bones will follow.